1. Field of the Invention
The present invention relates to a ratchet tool, and more particularly to a ratchet tool having an improved pawl engaging mechanism for increasing a driving engagement to the driving shank, and for increasing a driving torque to the driving shank and thus to the fasteners.
2. Description of the Prior Art
Typical ratchet tools or ratchet mechanisms comprise a block or cartridge attached to a handle, a rod or gear rotatably engaged into the block or cartridge for coupling to a driving shank, and two pawls slidably engaged into the block or cartridge for being biased to engage with the rod or gear, in order to determine the driving direction of the driving shank.
For example, U.S. Pat. No. 5,687,820 to Lin, and U.S. Pat. No. 5,974,915 to Chou disclose two of the typical ratchet tools or ratchet mechanisms each also comprising a driving shank selectively coupled to a base cartridge of the handle with two pawls, and the pawls each includes a number of teeth for engaging with the teeth of the rod or gear or driving shank, in order to control the driving direction of the driving shank relative to the handle.
However, the teeth of the pawls and the teeth of the rod or gear or driving shank normally include a uniform or regular gear tooth structure, and normally, only one of the teeth of the pawls may be suitably engaged with the teeth of the rod or gear or driving shank particularly when the pawls are biased or forced to engage with the teeth of the rod or gear or driving shank by the handle, such that a weak engagement and a decreased driving torque may be formed between the pawls and the driving shank.
U.S. Pat. No. 6,227,077 to Chiang, and U.S. Pat. No. 6,250,183 to Chiang disclose two further typical ratchet tools or ratchet mechanisms each also comprising a driving shank selectively coupled to a base cartridge of the handle with two pawls, and the pawls each includes a number of teeth for engaging with the teeth of the rod or gear or driving shank, in order to control the driving direction of the driving shank relative to the handle.
However, similarly, the teeth of the pawls and the teeth of the rod or gear or driving shank also include a uniform or regular gear tooth structure, and only one of the teeth of the pawls may be suitably engaged with the teeth of the rod or gear or driving shank particularly when the pawls are biased or forced to engage with the teeth of the rod or gear or driving shank by the handle, such that a weak engagement and a decreased driving torque may be formed between the pawls and the driving shank.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ratchet tools.